Electric precipitating apparatus



y 1950 J. u. F. ANDERSEN 2,508,133

ELECTRIC PRECIPITATING APPARATUS Filed July 51, 1947 INVENTOR M; m fill/MA M m Z M; M 4m ATTORNEY Patented May 16, 1950 2,508,133 ELECTRIC PRECIPITATING APPARATUS Joakim Ulrik Frederik Andersen, Copenhagen, Denmark, assignor to F. L. Smidth & 00., New York, N. L, a corporation of New Jersey Application July 31, 1947, Serial No. 764,983 In Denmark August 29, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires August 29, 1964 3 Claims.

This invention relates to electric precipitation apparatus of the type which includes ionizing electrodes in the form of wires and hollow collecting electrodes, through which the ionizing wires extend. More particularly, the invention is concerned with an electric precipitator of the kind described, which includes novel means for subjecting the collecting electrodes to vibration to prevent the accumulation of precipitated matter thereon.

Electric precipitators containing ionizing electrodes in the form of plain or corrugated sheets are now commonly provided with means for subjecting the electrodes to vibration in order to free them of dust accumulations, which would reduce the efficiency of the electrodes and might lead to a flash-over between the electrodes. The vibration of the collecting electrodes of sheet form can be accomplished by relatively effective and simple means but, heretofore, so far as I am aware, no means have been developed for the vibration of hollow collecting electrodes surrounding the ionizing electrodes.

The present invention is directed to the provision of an electric precipitator containing ionizing wires and hollow collecting electrodes enclosing the wires, the apparatus including a simple and efficient means for vibrating the hollow elec trodes for the removal of dust therefrom. In the precipitator of the invention, the hollow electrodes are attached to a plate supported resiliently within a casing for movement in the direction of the length of the hollow electrodes and, prefer ably, the collecting electrodes depend from the plate. The plate is mounted between the gas inlet and gas outlet from the casing, and sealing means are provided. for preventing leakage of gas between the edge of the plate and the inner wall of the casing. The vibration of the plate and electrodes may be advantageously effected by electromagnetic means.

For a better understanding of the invention, reference may be made to the accompanying drawing, in which the single figure is a vertical sectional view through a precipltator constructed in accordance with the invention.

The precipitator illustrated in the drawing comprises a metal casing i into which the gases to be cleaned enter through an inlet 2. The treated gases leave the casing through an outlet 3 and the precipitated solid material is collected in a hopper 4 at the lower end of the casing and discharged through the hopper outlet 5. The casing contains pairs of electrodes consisting of ionizing wires 6 extending through hollow collecting electrodes 1, preferably cylindrical in form. The wires are supported at the upper ends in any convenient manner (not shown) and kept taut by weights 8 attached to their lower ends. The wires are connected to the negative terminal ,of a D. C. high tension source and the other terminal of the source is connected to ground, as is also the casing through the line 9.

A plate iii of approximately the same size and shape as the cross-section of the casing is mounted within the casing between the gas inlet and gas outlet. The plate is supported for limited up and down movement and is preferably suspended from the casing by means of springs II. The plate has an opening for each hollow electrode and the electrode extends through the opening and has its upper end turned outwardly, as indicated at 1a, to rest upon the upper surface of the plate. The edge of the plate is provided with a peripheral flange l 2, which dips beneath a body of liquid l3 in a circumferential channel 14 mounted on the inner wall of the casing, With this arrangement, gases entering the casing through inlet 2 cannot leak between the edge of the plate and the casing wall but must pass through the hollow electrodes on their way to the gas outlet 3.

The tubular electrodes are secured together at their lower ends by connections l5 and they are also connected through springs Hi to the inner wall of the casing. The lower ends of electrodes 1 lie a substantial distance below the level of gas inlet 2 and, in passing through the apparatus, the gases enter the casing, flow downwardly to the lower ends of electrodes 1, and then reverse direction and pass upwardly through the electrodes to the top of the casing, whence they escape through outlet 3. The abrupt change of direction made by the gases at the lower ends of the electrodes 1 causes the coarser dust particles to be thrown out of the gas stream by centrifugal action. Most of the dust precipitated on the inner surfaces of electrodes 1 slides downwardly along those surfaces but some dust adheres to the electrodes and must be removed for efiicient operation. With the construction described, it will be apparent that the plate HI and the tubular electrodes may be vibrated in the direction of the length of the electrodes, and such vibration will free the inner surfaces of the electrodes of accumulated dust.

The vibratory movement of the plate and electrodes i is effected by means of a magnet H, which may be mounted to depend from the upper end of the casing to lie close to the top of plate I. An armature l8 for the magnet is mounted on the top of the plate and the magnet is supplied with current through lines l9 passing through the top of the casing. The magnet is intermittently energized by known means and causes the plate and the hollow electrodes depending therefrom to be vibrated vertically, such vibration being of limited amplitude so that the flange l2 on the plate is not raised out of the body of liquid l3. The small up and down movements of the plate and electrodes have been found to achieve the desired purpose of freeing the inner surface of electrodes 1 from accumulated dust, which impairs the operation of the apparatus.

I claim:

1. An electric precipitator, which comprises a casing having an inlet for gases to be treated, an outlet for treated gases, and an outlet for precipitated material, a plurality of vertical hollow collecting electrodes within the casing, an ionizing electrode within each collecting electrode, a plate of substantially the shape and size of the cross-section of the casing mounted across the casing between the gas inlet and gas outlet, the collecting electrodes extending through openings in the plate and being supported thereby, means for supporting the plate for limited vertical movement, sealing means for preventing the leakage of gases between the edge of the plate and the casing, resilient means for positioning the. lower ends of the electrodes with relation to the casing, and magnetic means acting intermittently to raise the support and collecting electrodes and then release them.

2. An electric precipitator, which comprises a casing having an inlet for gases to be treated, an outlet for treated gases, and an outlet for precipitated material, a plurality of vertical hol low collecting electrodes within the casing, an ionizing electrode within each collecting electrode, a plate of substantially the shape and size of the cross-section of the casing mounted across the casing between the gas inlet and gas outlet, the collecting electrodes extending through openings in the plate and being supported thereby, flexible means suspending the plate from the casing for limited vertical movement, sealing means preventing the leakage of gases between the edge of the plate and the casing, resilient means for positioning the lower ends of the electrodes with relation to the casing, and means acting intermittently on the plate to vibrate the support and collecting electrodes vertically.

3. An electric precipitator, which comprises a casing having an inlet for gases to be treated, an outlet for treated gases, and an outlet for precipitated material, a plurality of vertical hollow collecting electrodes within the casing, an ionizing electrode within each collecting electrode, a plate of substantially the shape and size of the crosssection of the casing mounted across the casing between the gas inlet and gas outlet, the collecting electrodes extending through openings in the plate and being supported thereby, means for supporting the plate for limited vertical movement, said plate having a flanged peripheral edge close to the casing wall, a liquid-containing vessel extending circumferentially around the inside of the casing wall, the flanged peripheral edge of the plate entering the liquid to prevent a flow of gas around the edge of the plate, and magnetic means acting intermittently to raise the support and collecting electrodes and then release them.

JOAKIM ULRIK FREDERIK ANDERSEN.

REFERENCES CITED The following references are of record in the flle of this patent:

FOREIGN PATENTS Number Country Date 329,062 Germany Oct. 28, 1919 468,972 Germany Feb. 26, 1924 745,551 France Apr. '7, 1902 

